*{margin: 0;padding: 0;}
body{
    width: 100%;
    height: 100%;
    position: relative; 
    color: #3387a1;
    font-size: 12px;  
    font-family: 宋体, Helvetica, Arial, Verdana, sans-serif;
    } 
html{
    width: 100%;
    height: 100%;
}
a{
    text-decoration: none;
    text-align: center;
    color: #3387a1;
}
a:hover{
    color: #3387a1;
}
.nav{
    position: fixed;
    top: 0;
    left: 0;    
    background: #fff;
    opacity: 0.7;
    width: 100%;
    height: 60px;
    padding-left: 215px;
}
.nav li{
    font-size: 18px;
    list-style: none;
    float: left;
    line-height: 60px;
    width: 150px;
    text-align: center;
    color: #3387a1;
}
.nav a{
    width: 100%;
    height: 100%;
    display: block;
}
.nav a:hover{
    color: #fff;
}
.nav li:hover{
    background: #dddddd;
    color: #fff;
} 
.nav-wrap ul{
    display: none;
}
li.nav{position:relative}
.nav-wrap li{
    background:#bbb;
    display:none;
    position:absolute;
    width:100px;
    box-shadow: 0 1px 2px 0px gainsboro
}
#homework{
    width: 100%;
    height: 800px;
    background: url("../images/3.jpg") no-repeat ;
    background-size:cover;
    background-attachment:fixed;
}
#homework a{
    font-size:25PX;
    color: #fff;
    line-height:35px;
}
#homework a:hover{
    color: #333;
}
.H{
    position: absolute;
    right: 210px;
    bottom: 70px;
    opacity: 0.8;
}
.H img{
    width: 60px;
    height: 60px;
    background: #f56600;
    border-radius: 30px;
    position: relative;
    top: 15px;
    margin-right: 20px;
}
.H .muxi{
    background: #fff;
}
